Printing surface



J. A. COREY. PRINTING SURFACE.

APPLICATION FILED MAR- 4, I919.

Patented Au. 22, 1922.

IIIII I Inventor Attorney-- UNITED sTAras T OFFICE.

PRINTING SURFACE.

Application filed March 4, 1919. Serial No. 280,668.

(GRANTED UNDER THE PROVISIONS OF THE ACT OF MARCH 3, 1921, 41 STA T. L,1313.)

To all whom it may concern:

Be it known that 1, JAMES ALBERT COREY, an American citizen, residing at18 Manor Mansions, Belsize Grove, Hampstead, Lon: don, N. England, haveinvented certain new and useful Improvements Relating to PrintingSurfaces (for which I have filed application in Great Britain February25, 1918, application No. 3,269), of which the following is aspecification.

This invention relates to printing surfaces.

The invention has for one of its objects to produce cylindrical printingsurfaces by electrotyping and has especial utility in ts application torepetition work such for 1nstance as bank notes, postage stamps, and thelike with respect to which it is diflicult in a practical way to ensuresubstantial identity of image and tone from a number of printingsurfaces repeated by engraving or photogravure from the same original.

The use of fiat intaglio printing surfaces duplicated from the originalby eleotrotyping is known for printing in flat bed printing-machines butthe use of intaglio and other printing surfaces in rotary printingmachines is restricted bythe practical difliculty referred to.

The invention has thus among its objects to secure substantial identityof impression and tone values from a number of cylindrical printingsurfaces by their production by electrotyping from the original.

The invention broadly comprises the.production of cylindrical printingsurfaces as relatively thin, hard and dense deposits by electrotyping,and it comprises the methods hereinafter described v and the productsthereof.

According to the invention the electrotype printing cylinder may beproduced as arelatively thin and hard deposit from an original ofidentical cylindrical form or it may be produced from an original in theflat, or again the electrotype in the form of a relatively thin and harddeposit may be produced in the fiat and subsequently shaped to acylindrical form as hereinafter described.

The invention is illustrated diagrammatioall in the accompanying drawingin whic Figure 1 represents a diagrammatic section lllustrating themanner in which the mother is formed upon the master.

Figure 2 is a similar section showing the manner in which theelectrotype is produced within the mother, and c F gure 3 illustrates ina similar view a sectlonal viewof the electrotype produced.

In carrying the invention into effect according to one modification inthe productlon of an intaglio printing cylinder, I produce an original aof identical cylindrical form to that to be electrotyped and from thisoriginal or master a I produce a number of identical cylindricalelectrotypes d which are relatively thin and hard. For repetition worksuch as postage stamps the original image may be multiplied as manytimes as required, assembling these copies in register and thenproceeding in the samev way as in reproducing the original of a singleimage. The master cylinder 0. is prepared for the production of a reliefor Specification of Letters Patent. Patented Aug, 22, 1922,

mother 6 by treating the surface so that the deposit may be separatedfrom it without injuryor loss of definition to the engraved image. Thismay be conveniently done by 'a deposit of silver upon. .the engravedsurface or by any other methods commonly practised by the el'ectrotyper.A layer of metal such as copper is then electro-deposited upon themaster cylinder a and the deposit while being relatively thin may bemade sufliciently thick for example for the cylinder to beself-supporting when stripped from themaster, that is, it may be of sucha thickness and degree of hardness that it will spring back or not be sothick as to be incapable of being gently forced back into exact circularform, thus understood that a very thin deposit is practicable and themost economical. For this purpose the electro-deposition isv effected inthe use of high current densit es and in the circulation of theelectrolyte, or in the movement of the cathode therein. The relief ormother cylinder b thus produced together with the master a may be mounted upon a mandrel in a lathe or grinding machine and be ground true andthe deposit trimmed to the desired length by cutting just through thedeposit to the original or master cylinder a at both ends. Alongitudinal cut as at e is then made through the deposit 6 parallelwith the longitudinal printing cylinder having a continuous doctoring orwlping surface from such a mother cylinder, the following method may beemployed. v

The longitudinal edges of the mother or relief cylinder 6 where thegylinder is slit at e are brought together in alignment, and in order tomaintain the edges in position and'to make good electrical contact I maytack the edges with solder at a number of points and fill in any slightgap that re mains in theintervals between the solder points with the waxor other suitable non conducting material and carefully scrape away anysuperfluous wax so as to make an uninterrupted curved surface over theslit posit.

ate. The wax may then carefully be polished with graphite to make itelectrically conductive and so that the deposit may then be madecontinuous around the entire surface ofthe relief or mother cylinder.

The mother cylinder or relief 6 is then mounted in a holder by which itmay be fixed to a spindle by which it may be rotated within theelectrolyte. The inner surface carrying the image may be prepared forseparating the deposit by silvering or by other means and the deposltmaythen be made under the same conditions and to the posit will be now madeon the inside of the ,cylinder 6 instead of upon the outside, and

may be confined tominima thicknesses of de- The deposlt having reachedthe desired thickness the mother cylinder or relief I) is separated fromthe mother I). For this purpose the solder joints at e are melted awayand boiling water may be poured as before upon the outer cylinder 5which will then expand and facilitate separation from movement.

the face plate of the machine concentric the inner cylinder 0!. Theouter cylinder 5 can then be grasped by the two ed es and gently sprungopen sufliciently to a low of slipping clear oil the inner cylinder dwithout damage to either. Any traces of the image that may appear inrelief on the inner surface of the cylinder are removed and in the sameoperation any inequality in thickness may be corrected by turning orgrindin For t is purpose a clamping forme may be employed composed oftwo semi-circular concave members provided with a flange at one end bywhich it may be clamped to the face plate of a drilling or similarmachine. The cylinder is now enclosed in thisforme and the twosemi-circular concave members are drawn up by binding screws until theygrip the cylinder sufliciently to prevent its The forme is now clampedon with the grinding or tool head and the plate and forme are graduallmoved so that the full length of the cyllnder will pass the grinding ortool head fitted upon the spindle, or the cylinder may remain stationaryand the spindle carrying the grinding or tool head may be graduallymoved. The cylinder carrying the intaglio image on its outer surfaceidentical in every respect with the image on the master cylinder ororiginal is now slipped over the expanding mandrel for mounting in theprinting machine ready for printing.

Where cylindrical electrotypes of exceptional thickness are produced, llmay provide metal filling strips for insertion into the gaps of theexpanding mandrel.

When producing relief printing surfaces according to the invention andwhere the surface of the relief has deep cuts or recesses, the reliefmother may be out on two longitudinal lines in diametrically oppositepositions with a view to ensure its separation from the final product.Furthermore the outside of the mother may be ground so that the mothermay be fitted into a holder adapted to receive it. Thus the inside aswell as the outside surface of the mother may have a constant diameter.

It will be understood that in the production of a cylindricalelect-rotype as hereinbefore described, there will be a relief formed onthe back of the deposit and this relief will be removed in grinding orturning. Furthermore in deposition the layer is apt to become thicker atthe ends and the grinding of the inner surface or the bore of theelectrotype may remove the increased thickness'of the ends and renderthe bore uniform. With a View however to avoid 'the thickening of thedeposit at the respec-' tive ends of the electrotype to which therespective connections are made, the anode which in depositing theelectrotype upon towards the end or ends and the respective shapes orsizes of the sections of the anode may be determined by trial with aview to ensure a substantially uniform deposit.

In carrying-the invention-into effect ac-.

cording to another modification of method, the original is produced inthe flat and a thin and hard metal relief is deposited thereon of such athickness that it may be bent to a circular shape. This relief is thenmounted in hollow circular fo-rmes so that the image ison the inside andso that a complete cylinder or mother is produced of true cylindricalform. A tube of suflicient thickness as hereinbefore described is thendeposited as a relatively thin and hard layer within the mother cylinderor relief.

In carrying the invention into effect according to another modificationof method in the use of an original in the flat or otherwise, I mayproduce a mould preferably in lead from the original preferably in theflat and produce a flat electrotype from the lead mould. This flat orsheet electrotype is deposited as a hard layer and to a suflicientthickness as hereinbefore described so that it may be bent into a truecylindrical form. Its edges are soldered, brazed or welded and thecylindrical electrotype produced is finished in the same manner asdescribed according to the first method.

In carrying the invention into effect according to another modificationof method, the mould preferably in lead, may itself be formed into acylindrical shape and a thin and hard cylindrical electrotype producedfrom the lead mould, the product being then finished as before. It willbe understood that this modification is not preferred-for fine work. I

I claim 1. A method of producing a jointless cylindrical electrotypeprinting surface, comprising the production of a flexible cylindric-almother of'relatively thin, hard and dense metal b electrotyping from acylindrical origina, splitting and stripping the mother from theoriginal and using the mother as a mould, substantially as described.

2. A method of producing a jointless cylindrical electrotype printingsurface, comprising the production of a flexible cylindrical mother ofrelatively thin, hard and dense metal b electrotyping from a cylindricalorigina after the exterior surface of the original has first beentreated for the. ready separation from it of the mother without injuryor loss of definition, splitting and stripping the mother from theoriginal and using the mother as a mould, substantially as, described.

3. A method of producing a jointless cylindrical electrotype printingsurface, comprising the production of a flexible cylindrical mother ofhard and dense metal by elect-rotyping from a cylindrical original, themetal being sufficiently thick to permit of the mother beingself-supporting but sufliciently thin to be incapable of permanentdistortion on release from the original,

splitting and stripping the mother from the original and using themotheras a mould, substantially as described.

4;. A method of producing a jointless cylindrical electrotype printingsurface, com.- prising the production of a flexible cylindrical motherof relatively thin, hard and dense metalby electrotyping from acylindrical original, splitting the mother from the original andstripping the mother from the original by pouring hot liquid over it,and then using the mother as a mould, substantially as described.

5. A method of producing a jointless cylindrical electrotype printingsurface, comprising the production of a flexible cylindrical mother ofrelatively thin, hard and dense metal by electrotyping from acylindrical original, splitting the mother by cutting on a longitudinalline, stripping the mother from the original and then bringing togetherinto alignment and contact the edges of the-mother at the part at whichit is cut and securing the edges together temporarily, then using themother as an electrotyping mould, then disconnecting'the edges andstripping the mother from the electrotype produced, substantially asdescribed.

6. A method ofproducing a jointless cylindrical electrotype printingsurface, comprising the production of a flexible cylindrical mother ofrelatively thin, hard and dense metal by electrotyping from acylindrical original, splitting the mother by cutting on a longitudinalline, stripping the mother from the original and then bringing togetherinto alignment'and contact the edges of the mother by the use of solderat the part at which it is cut and securing the edges togethertemporarily, then using the mother as an electrotyping mould,

then disconnecting the edges and stripping the mother upon a holder andusing the mother as a mould, siibstantially as described.

8. A method of producinga' jointless cylindrical electrotype printingsurface, comprising the production of a flexible cylindrical mother ofrelatively thin, hard and lindrical electrotype printing surface,comprising the production of a flexible cylindrical mother of relativelythin, hard and dense metal by electrotyping from a cylindrical original,splitting and stripping the mother from the original, then mounting themother upon a support and depositing the jointless cylindricalelectrotype printing surface Within the mould after first treating theinner face of the mother so that the jointless cylindrical printingsurface may be separated from it Without injury or loss of definition,substantially as described.

10. A method of producing a jointless cylindrical'ele ctrotype printingsurface, comprising the production of a flexible cylindrical mother ofrelatively thin, hard and dense metal by electrotyp-ing from acylindrical original, using the mother as a mould and then splitting themother and stripping the mother from 'the original by pouring hot liquidover it, substantially as described.

11. A method of producing a jo-intless cylindrical electrotype printingsurface, com-' the inner surface of the jointless cylindricalelectrotype printing surface stantially as described.

12. A. method of producing a jointless cylindrical electro'type printingsurface, comprising the production of a flexible cylindrical mother ofrelatively thin, hard and dense metal by electrotyping from acylindrical original, mounting the original with the mother upon itWithin a machine tool for grinding or machining the exterior of themother, splitting and stripping the mother from the original, and usingthe mother as a mould, substantially as described.

13. A cylindrical electrotype mother of hard, dense and flexible metalsufficiently thick to be self-supporting but sufliciently thin to beincapable of permanent distortion on release from the original or fromthe electrotype produced therein, substantially as described.

produced, sub- JAMESA-LBERT COREY:

